Geogrid Installation Procedures

• Geogrid Applications
• Geogrid Installation Procedures Pdf

Retaining Wall with Unreinforced Soil, Cross Section.Retainingwalls hold back potentially unstable wedges of soil. Depending on soiltype and other site conditions, unreinforced VERSA-LOK walls can bethree to four feet tall.If the weight of the VERSA-LOK wall unitsalone can't resist the force of an unstable soil wedge or any load ontop of it, then geogrid soil reinforcement is needed. Horizontal layersof geogrid provide tensile strength to hold the reinforced soil masstogether. The geogrid-reinforced soil mass becomes part of the retainingwall system, giving the system more size and weight to resistpressures from behind it. VERSA-GridSoil ReinforcementVERSA-Grid is lightweight and easy to install. It’s flexible, withvirtually no memory, so it lays flat after being unrolled. Just unrolland make sure the VERSA-Grid is rolled out continuously, perpendicularto the wall face.VERSA-Grid comes in multiple strength types.VERSA-Grid 3.0, VERSA-Grid 5.0 and VERSA-Grid 8.0 are the strengthscommonly used for landscape and commercial walls.

These VERSA-Gridstrengths are generally available in 6-ft. Wide x 150-ft. Long rolls(100 sq.yd.

For some residential walls, VERSA-Grid 1.5 isused, but only for walls up to 6 feet tall. It is available in 4-ft.wide by 50-ft long rolls (22 sq.yd. Estimating Geogrid QuantitiesThe length, vertical spacing, number of layers and strength of thegeogrids needed will vary with each wall project, depending on wallheight, loading, slopes, and soil and water conditions.

Geogrid Applications

Retaining wallstaller than 3 to 4 feet typically require a qualified professional civilengineer (P.E., licensed in the state of the project) to prepare aproject-specific, final wall design that shows the needed geogrid basedon actual site conditions. Consult with a local building code officialregarding permitting and wall design requirements.

VERSA-LOK and localVERSA-LOK representatives can provide contacts for engineers withsegmental retaining wall design experience who are licensed in yourstate.For preliminary geogrid estimates, your local VERSA-LOKrepresentative can assist in estimating geogrid lengths and quantities.VERSA-LOK’s can also help in preliminary estimates of geogrid quantities. The for each type of VERSA-LOK unit also includes VERSA-Grid estimating charts for that unit type, for common site conditions. Step 1The wall installation, including geogridinstallation, should be done in accordance with the project-specificfinal wall design and specifications, prepared by a qualified, licensedprofessional engineer (P.E.) and any applicable building codes andstandards. Prepare to install VERSA-Grid by placing VERSA-LOK units,backfilling and properly compacting soil fill andup to the height of the first (lowest) soil-reinforcement layer that isspecified on the final, professionally engineered construction drawings(P.E. Stamped plans) (Figure 1, below). Several layers (lifts) of soilfill will need to be placed and then compacted to reach the height ofthe first geogrid layer elevation. Note that the maximum allowablethickness for loose soil lifts, before compacting, varies with type ofbackfill soil and equipment used.

Step 3Placing geogrid behind curves and corners requiresspecial layout and overlapping procedures. Never overlap geogrid layerswithout soil in between the layers; always provide at least three inchesof soil fill between overlapping geogrid layers. Slick surfaces of thegrid will not hold in place properly when placed directly on top of eachother. See illustrations in VERSA-LOKfor general guidelines for placing VERSA-Grid in curves or corners, andfollow the final wall design (P.E. Stamped plan) details andrecommendations. Questions, needed details and other clarificationsshould be directed to the final wall design engineer.

Geogrid Installation Procedures Pdf

Step 4Correctly position the next of VERSA-LOK units on top of the grid. Insert two VERSA-TUFF ®pins per unit in the upper units. Drive the pins through the grid andinto the receiving slots of the lower-course units. Use an extra pin anda mallet to set the pins firmly in the lower-course units.Step 5Removeslack by pulling the grid backward from the wall face and anchoring atback edge.

Place drainage aggregate against back of units and on top ofVERSA-Grid. (Figure 3, below).Step 6Place and compact the drainage aggregate.

Then place and compact soil backfill above the geogrid, starting at the wall units and working back, keeping the geogrid taut to avoid wrinkling. Step 7Place a minimum of six inches of soil backfill overthe geogrid layer before using any rubber-tired or tracked equipment ontop of it. Prevent fill movement and grid damage by driving equipmentslowly and turning gradually. Use only hand-operated compactionequipment within three feet of the wall face to avoid excessiveequipment loads and possible movement of wall units.Step 8Continueplacing additional courses, drainage material, compacted soil backfilland VERSA-Grid according to final wall design drawings. Only a fewcourses of units should be stacked before backfilling.

The number ofcourses that can be stacked without backfilling and the methods forplacing additional units varies with the type of VERSA-LOK unit used.See the VERSA-LOKfor the type of VERSA-LOK unit being installed. Repeat steps 2 through 8.This is simply a general overview of the grid installation portion of wall construction.

See the final wall design (P.E. Stamped plans), and see other VERSA-LOK. Questions, needed details and other clarifications should be directed to the final wall design engineer.